This section provides background information related to the present disclosure, which is not necessarily prior art.
Circuit interrupting devices may include two function which server to interrupt a power distribution system. One function operates to isolate a fault condition which may be reclosed manually or automatically after clearing the fault condition to restore the circuit. Such fault conditions in a power distribution system can occur for any number of reasons and are typically transient. Reclosing after the fault is cleared provides for quick service restoration. A second function operates to interrupt the power distribution circuit by disconnecting a portion of the power distribution system. This interrupt function is typically enabled for maintenance or repair and may be manual or automated in response to an interrupt request other that a fault condition.
To enable these two functions, a typical circuit-interrupting device may include a circuit interruption switch such as a vacuum interrupter and a circuit disconnect switch such as a isolating disconnect, which are separate, yet integral. Incorporating the sequenced operation of the switches presents a number of design challenges including: mechanical “early trip” of the vacuum interrupter, proper timing of the vacuum interrupter and isolating disconnect so that the isolating disconnect do not open or closed under normal load or fault conditions, possible vacuum interrupter malfunction (welding), potential operator error resulting in an incomplete reset of the circuit interrupting device, and unbalanced torque and energy required for opening or closing the circuit interrupting device.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.